The only times that there are huge flames are when the grease is dripping onto the coals, or the kindling is burning.
BTW, this is how to light a weber -
Get some newspaper and kindling, ranging from a small twig to 1/4" thick or so. Open the vents on the bottom and take out both grilles, roll up three newspapers, and stick one in each. Then crumple up another newspaper and put it in the grill in the middle. Stack the twigs around it. Put the top grille on and put the coals on top. Roll up a newspaper and light the end with a match. Use it to light the three newspapers sticking out of the bottom. You should get a pretty nice fire going, then when the coals are grey, pick up the top grille, put the bottom grille in, and then pour the coals onto the bottom grille. Then clean off the top grille and put your food on it.
My rule of thumb - if you need to close the vents, there's too much charcoal. I start off small and if it doesn't cook, I add more. My dad, on the other hand, starts off with too much then needs to close the vent. One time it was about 10 degrees farenheit (-10 or so for you celcius people) and I was grilling a lot, so I put used like 4 lbs of charcoal. It didn't turn out well. The burgers looked fine, but the middle was only lukewarm. There's probably a thread about it somewhere if you're inclined to look. That was one hot motherfucking fire. It melted a bunch of snow that got too close.
*Like any real man, I use my grill 12 months a year and in any weather condition. Not like those pussies who only use it in the summer and only when it isn't raining.